To schedule a game, start a new thread and put the time slot at the front of the subject. That way when people sort the forum alphabetically they'll see all the game slots in chronological order, like so:

FRI-01 Masks in the Dark (4 players)

SAT-01 D&D, 6th Edition (5 players)

You'll want to provide all the usual information: how many people you're looking for, the game system, etc. Putting that info in the thread title is not a bad idea. Coming back and editing your thread title to show how many slots you have left, also a good idea:

SAT-01 Masks in the Dark (Blades Hack, 4 players needed)

If you're not sure you want to commit to a scheduled game, or you just want to kick around ideas, get thee to the Brainstorming Games forum.

BE HONEST

If you're offering to run/facilitate a game, people are going to assume you know the rules really well and have played it before. If you don't or you haven't, it's extremely good karma to say so up front. People will still play, but they won't show up with false expectations. They may even make the effort to learn the game ahead of time and help you out. Be honest.

Same thing for homebrewed, kitbashed, experimental prototypes: we loves gaming dangerously, and we loves cutting edge playtesting, but we also like making informed decisions. Tell people what they're signing up for.

FINALIZE YOUR ROSTER

A few days before Go Play NW you'll need to go back into your thread and post a list of who is playing in your game, say whether you still have slots available, etc. That's the list we'll print and post on the wall. We're not going to go through the threads and interpret who's playing and who isn't -- that's on you.